A series of Dy1-xBixO1.5 (0.00 ≤ x ≤ 0.50) compositions were prepared by conventional solid state reactions of Bi2O3 and Dy2O3. X-ray diffractometry, ac-impedance spectroscopy and scanning electron microscopy were used to characterize the structure and properties of these compositions. All the compositions except x = 0.44 exist as composites of either rhombohedral and C-type rare-earth oxide phases or rhombohedral and fluorite type phases. At x = 0.44, a rhombohedral phase is observed which can broadly be explained on a sub cell with unit cell parameters: asub = 3.7728(1) Å and csub = 9.5541(5) Å, V = 117.77(1) Å3, Z = 3. The exact structure is a super lattice of this unit cell. The unit cell of the super- and sub structures are related as: asuper = bsuper˜4 X asub and csuper ˜ 2 X csub. The studied Bi2O3–Dy2O3 systems showed an oxide anionic conductivity and the conductivity increases with the increase in Bi concentration as well as temperature. Typical activation energies of all compositions are within 1.1 to 1.2 eV. At 800 K, the highest conductivity is observed for the composition Dy0.50Bi0.50O1.50 in the series. The observed maximum conductivity is lower than δ-Bi2O3, but significantly higher than the stabilized zirconia.